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Barbara Pugliese

10B – LEWIS STRUCTURES AND VSEPR H C N O P Cl

Can different atoms have the same number of valence electrons? Use examples from your data table and explain how this is possible according to the periodic ...

Which gives the most information about the 3D structure of the molecule, the Lewis structure or the molecular model? Page 3. 10B – LEWIS STRUCTURES AND VSEPR / ...

10B answer sheet

Lewis structures and VSEPR - Essential Chemistry Teacher Lab Manual | PASCO

10B answer sheet
10B ­ LEWIS STRUCTURES AND VSEPR

Part 1 Analysis ­ Lewis structures of atoms

Table 1 ­ Lewis structures of atoms

Atom Symbol (draw Lewis
structure here)

Total number of electrons
in atom

Number of valence electrons

Number of lone pairs
of electrons

Number of unpaired electrons

Number of bonds that can form

Model color for
atom

Number of holes on model
atom

H

C

N

O

P

Cl

Part 1 Questions ­ Lewis structures of atoms
1. What is the relationship between bonds that can form and holes on the model atom?

2. Can different atoms have the same number of valence electrons? Use examples from your data table and explain how this is possible according to the periodic table.

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10B ­ LEWIS STRUCTURES AND VSEPR / STUDENT HANDOUT 3. Carbon is a key element in the formation of living things. Why is the number of bonds carbon
makes important for living things?
4. Does the absence of holes on an atom always indicate the presence of lone pairs of electrons? Why or why not?
Part 2 Analysis ­ Lewis Structures of molecules
Table 2 ­ Lewis structures of molecules Lewis
Structure
Structural formula Chemical Formula
Part 2 Questions ­ Lewis structures of molecules
1. Which gives the most information about valence electrons, the Lewis structure or the molecular model?
2. Which gives the most information about the 3D structure of the molecule, the Lewis structure or the molecular model?
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Part 3 Analysis ­ VSEPR

Table 3 ­ VSEPR Chemical formula

Lewis Structure

10B ­ LEWIS STRUCTURES AND VSEPR / STUDENT HANDOUT

Number of bonding electron domains

Number of non-
bonding electron domains

Molecular shape of central atom

H2O

PCl3

CO2

CH4

CH2O
Part 3 Questions ­ VSEPR
1. Molecules with 2 bonding electron domains on the central atom can be either linear or bent. Which molecules from Table 3 have 2 bonding electron domains? Which is linear and which is bent?

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10B ­ LEWIS STRUCTURES AND VSEPR / STUDENT HANDOUT 2. Molecules with 3 bonding electron clouds can be trigonal planar (flat) or trigonal pyramidal.
Which molecules from Table 3 have 3 bonding electron domains? Which is trigonal planar, and which is trigonal pyramidal?
3. Compare the Lewis structures of the molecules you built. What causes the shape of a central atom to change from linear to bent, or from planar to pyramidal? Explain your answer.
4. Molecules with 4 bonding electron domains and 0 non-bonding electron domains have a tetrahedral shape. Which molecules from Table 3 have a tetrahedral shape?
5. For the molecule below, identify the geometry of each of the four central atoms (N, C, C, O) based on the electron domains. Verify your answer by building the molecule.
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